Ive run into this also. But as an electrician, when things got so busy that i couldnt keep up, i kept raising my rates and bids. If they were accepted, it made it worth while to take on additional employee.
My rates are still pretty high, but i have more business than i can handle. And im retired to boot. No employees any more.
If you can install it yourself, more better for you. As long as its done correctly and safely. Ive seen some very scary homeowner installed jobs….i mean deadly unsafe. Including one idiot that installed an air cooled unit inside his garage.
Contractors are also burdened with overhead, work comp and contractor insurance, matching 401k, health insurance, etc. it all adds to cost.
One quick thing about your new install, read the manual closely as generac has recently added the need to run a separate control wire neutral wire that runs out to the generator T1neutral lug. There is no longer a jumper within generator. Its a new NEC rule. This has been messing up alot of recent installs. If missed, the battery charger doesnt operate.